Screen for producing photomechanical printing-plates.



l. A. H. HATT.

SCREEN FOR PRODUCING PHOTOMECHANICAL PRINTING PLATES.

APPLICATION FILED JUNE l0. I908.

B, l'zfififi Patented Mar. 14,1916.

tnwa'em JOSEPH ARTHUR H. HATT, OF YORK, N. Y.

SCREEN FOR.PRQDUCI1\TG PHOTOMECHANICAL PRINTING-PLATES.

Specification of Letters Patent.

Patented Mar. is, rare.

Application filed June 10, 1908; Serial No. 437,767.

T 0 all whom it may concern:

Be 1t known that I, JOSEPH ARTHUR H.

I'Lvr'r, a citizen of the United States, re-' for Producing Photomechanical Printing'-' llates, of which the following is a specification.

The invention relates to screens for making photomechanical printing plates and has for its object providing a screen which will give,v superior results in producing plates both as to the modeling and the preservation of the various tints or tones and also with respect to the other features desirable in a printing plate; also to provide a screen with which a perfect halftone negativeknown to the art as a high light negative may be made. Such negative, owing to the translucency of the screen in all its parts, may be made so as to be completely opaque to the action of light on the sensitive plate, in certain parts of the picture known to the art as high lights. To provide further a screen which will produce superior gradations or modeling, from the middle tints to the high lights, thus doing away with a large amount of manual labor known as finishing or reetching or fine etch- Other objects of invention will in part be obvious and will in part more fully appear herein.

The invention consists in the novel articlcs, arrangements, combinations and improvements herein shown and described.

The accompanying drawings serve in conncctirnwith the description to illustrate the principles of the invention.

Of the drawings: Figure, 1 illustrates, somewhat diagrammatically, a form of screen constructed in accordance with the principles of the invention; and Fig. 2 illustrates a different form of screen so constructed.

Referring to the accompanying drawings, which it will be understood by those skilled in the art are on a very large scale as compared to the screens which they are used to illustrate or explain, a screen 1 is shown, the parts thereof being translucent. The body of the screen mayconsist of glass or any other suitable material. Upon the surface thereof rulings or tints or shadings are produced for the purpose of giving parts of less translucency than the body of the screen. According to certain features of the invention a screen is provided of three different degrees of translucency, and, if desired, the parts of less tra'nslucency may be secured by having a ruling or tinting of a given degree of translucency and super lmposmg said ruling or tinting at certain portions thereof to provide parts of less translucency. According to one feature of the invention also it is intended to provide a screen having the part of intermediate translucency of substantially twice the area of the parts of the greatest and least translucency, said least and greatest parts being of substantially equal area with each "other. In the drawings herewith a ruled or tinted portion 2 is shown upon the plate 1 leaving substantially clear or entirely translucent portions 3 therebetween. Parts 4 of still less translucency than the parts 2 are also shown and, as hereinbefore indicated, they are produced by superimposition of the parts 2 on each other.

By the use of a screen such as is provided by this invention the advantages hereinbefore enumerated are secured. There are no entirely opaque parts which cut ofl' certain portions of the light and thus necessarily impair the modeling in the plate and destroy or throw out of proportion or harmony certain of. the tints or tones of the picture. Furthermore by having the light act through a screen such as this the diffusive action necessary with the ordinary partly opaque screen, and for which a camera is essential, is done away with. Other,

advantages are also realized throughthe use of the present invention.

What I do claim as my invention and desire to secure by Letters Patent, is:

1. A screen for making photo-mechanical printing plates including in combination a plurality of contiguous and continuous areas, of varying light transmitting power, the areas of greatest light transmitting power being substantially surrounded by areas of intermediate light transmitting power, and areas of least light transmitting power substantially surrounded by areas of intermediate light transmitting power.

2. A screen for making photo-mechanical printing plates including in combination a plurality of contiguous and continuous substantially equal areas of varying light transmitting power, the areas of greatest light transmitting power being substantially surrounded by areas of intermediate light transmitting power, and areas of least light transmitting power substantially surrounded by areas of" intermediate light transmitting power. 7

3. A screen for making photo-mechanical printing plates including in combination a plurality of contiguous and continuous substantially equal areas of varying light transmitting power, and comprising areas of least light transmitting power, areas of greatest light transmitting power, and areas of intermediate light transmitting power, said last named areas being greatest in number, the areas of least light transmitting power being substantially surrounded by the areas of intermediate light transmitting power, the areas of greatest light transmitting power being surrounded by the areas of intermediate light transmitting power, said areas of greatest and least light transmitting power being contiguous. to each other, all parts of the screen being light transmittin 4. A screen for making photo-mechanical printing plates including in combination aplurality of contiguous and continuous areas, said areas being substantially equal in area and substantially the same in form, of varying light transmitting power the areas of greatest light transmitting power being substantially surrounded by areas'of intermediate light transmitting power, and areas of least light transmitting power substantially surrounded by areas of intermediate light transmitting power.

5. A screen for making photo-mechanicalprinting plates including in combination a plurality of areas, said area's being substantially equal in area and substantially the same in form, of varying light transmitting power, and comprising areas of least light transmitting power, areas of greatest light transmitting power, and areas of intermediate light transmitting power, said last named areas being greatest in number, the areas of least light transmitting power being substanti ally surrounded by the areas of intermediate light transmitting powenthe areas of greatest light transmitting power being surrounded by the areas of intermediate light transmitting pow-er, said areas of greatest and least light transmitting power being contiguous to each other, all parts of the screen being light transmitting 6. A screen for making photo-mechanical plates having its surface consisting of a plurality of contiguous and continuous areas, all of said areas being light transmitting, some areas being of greatest light transmitting power, and some of least light transmitting power, and having areas of intermediate light transmitting power, said areas. of intermediate light transmitting powerbeing of greater sum total area than the sum total area of those of greatest or of those of least light transmitting power, said areas of least light transmitting power being separated from each other in certain directions only by areas of intermediate light transmitting power. V

7. A screen for making photo-mechanical printing plates the surface of said screen consisting of a plurality of successively adjoining areas, each area being of one degree of light transmitting power throughout, and all of said areas being light transmitting and certain of said areas being transparent or, fully light transmitting, the areas of least light transmitting power being separated from each other in certain directions only by areas of intermediate light transmitting power.

8. A screen for making photo-mechanical printing plates including in combination a plurality of contiguous and continuous areas of yarying light transmitting power, the areas of intermediate light transmitting power being'bounded on their outerperiphcries in part by areas of least light t'ansmitting power, and in part by areas of greatest light transmitting power, all parts of the screen being light transmitting.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

J. ARTHUR H. HATT.

Witnesses:

JOHN D. Mono-in, KATHAmNE SEXTON. 

